Plating apparatus and plating solution agitating method

ABSTRACT

Provided is a plating apparatus and a plating solution agitating method that can agitate a plating solution without using a paddle.A plating apparatus 1000 includes a holder cover 50 disposed in a substrate holder 30 and configured to rotate with the substrate holder when the substrate holder rotates. The holder cover is configured to have a lower surface immersed in the plating solution with the lower surface positioned below a surface to be plated of a substrate. The lower surface of the holder cover is provided with at least one cover groove extending in a direction intersecting with a rotation direction of the holder cover.

TECHNICAL FIELD

The present invention relates to a plating apparatus and a plating solution agitating method.

BACKGROUND ART

Conventionally, there has been known what is called a cup type plating apparatus as a plating apparatus that can perform a plating process on a substrate (for example, see PTL 1). Such plating apparatus stores a plating solution while including a plating tank with an anode therein, a substrate holder that holds the substrate as a cathode, and a rotation mechanism that rotates the substrate holder.

Furthermore, conventionally, there has been known a technique of agitating the plating solution in the plating tank and supplying sufficient metal ions to vias formed on a substrate surface by arranging a paddle in the plating tank that reciprocates parallel to the surface of the substrate and agitates the plating solution (for example, see PTL 2 and PTL 3).

CITATION LIST Patent Literature

-   PTL 1: Japanese Unexamined Patent Application Publication No.     2008-19496 -   PTL 2: Japanese Unexamined Patent Application Publication No.     2009-155726 -   PTL 3: U.S. Pat. No. 7,390,383

SUMMARY OF INVENTION Technical Problem

In the cup type plating apparatus exemplified in the above-described PTL 1, for example, arranging a paddle exemplified in PTL 2 and PTL 3 in the plating tank may be considered. However, in this case, near both ends in a reciprocating moving direction of the paddle, a moving speed of the paddle may decrease and thus a uniformity of a plating film formed on the substrate may possibly decrease. Alternatively, when the paddle makes an instantaneous stop, a shadow of an electric field may possibly be formed on the substrate, in which case also, the uniformity of the plating film may possibly decrease.

Furthermore, when the above-described paddle is disposed in the plating tank, the plating apparatus may possibly increase in size.

The present invention has been made in view of the above, with an object to provide a technique of agitating the plating solution without the paddle.

Solution to Problem

[Aspect 1] To achieve the above-described object, a plating apparatus according to one aspect of the present invention includes a plating tank configured to store a plating solution, an anode being disposed in an inside of the plating tank, a substrate holder disposed above the anode and configured to hold a substrate as a cathode, a rotation mechanism configured to rotate the substrate holder, and a holder cover disposed to the substrate holder and configured to rotate with the substrate holder when the substrate holder rotates. The holder cover is configured to have a lower surface immersed in the plating solution and positioned below a surface to be plated of the substrate. The lower surface of the holder cover is provided with at least one cover groove extending in a direction intersecting with a rotation direction of the holder cover.

According to this aspect, when the substrate holder rotates and causes the holder cover to rotate, the lower surface of the holder cover provided with the cover groove can agitate the plating solution. Accordingly, the plating solution can be agitated without a paddle. As a result, a use of the paddle causing the uniformity of the plating film to decrease or the plating apparatus to increase in size can be suppressed.

[Aspect 2] In aspect 1 described above, the holder cover may have a ring shape in a bottom view.

[Aspect 3] Aspect 1 or 2 described above may further include a turbulence generating member disposed in a position below the substrate and above the anode in the inside of the plating tank, the turbulence generating member being configured to generate turbulence in the plating solution flowing from below the substrate toward the substrate.

According to this aspect, the turbulence generating member generates the turbulence in the plating solution, thus ensuring the plating solution to be effectively agitated.

[Aspect 4] In aspect 3 described above, the turbulence generating member has an internal flow passage configured to communicate a lower end of the turbulence generating member with an upper end of the turbulence generating member, and the plating solution heading toward the substrate flows through the internal flow passage. The internal flow passage in a bottom view of the turbulence generating member may have an Archimedean spiral shape.

According to this aspect, when the substrate holder rotates, an electric field between the anode and the substrate being hindered by the holder cover can be suppressed as much as possible while causing the plating solution to be agitated.

[Aspect 5] In aspect 4 described above, the internal flow passage may be provided with a protrusion configured to generate the turbulence in the plating solution flowing through the internal flow passage.

According to this aspect, compared with a case where the internal flow passage is not provided with the protrusion, the turbulence can be effectively generated in the plating solution flowing through the internal flow passage. Accordingly, the plating solution can be agitated more effectively.

[Aspect 6] In aspect 4 or 5 described above, the turbulence generating member may be configured such that when a plating process is performed on the substrate, the upper end of the turbulence generating member has a clearance with the surface to be plated of the substrate and is positioned above the lower surface of the holder cover.

According to this aspect, for example, compared with a case where the upper end of the turbulence generating member is positioned below the lower surface of the holder cover, the clearance can be decreased and a flow rate of the plating solution flowing through this clearance can be effectively increased. As a result, the plating solution can be effectively agitated.

[Aspect 7] To achieve the above-described object, a plating solution agitating method according to one aspect of the present invention is an agitating method of the plating solution of the plating apparatus according to any one of the above-described aspects 1 to 6. The plating solution agitating method includes rotating the substrate holder by the rotation mechanism with the lower surface of the holder cover immersed in the plating solution when the plating process is performed on the substrate.

According to this aspect, the plating solution can be agitated without using the paddle. Accordingly, the use of the paddle causing the uniformity of the plating film to decrease or the plating apparatus to increase in size can be suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an overall configuration of a plating apparatus according to an embodiment.

FIG. 2 is a plan view illustrating the overall configuration of the plating apparatus according to the embodiment.

FIG. 3 is a schematic diagram for describing a configuration of a plating module of the plating apparatus according to the embodiment.

FIG. 4 is a schematic diagram of a peripheral configuration of a substrate according to the embodiment in a state where the substrate is immersed in a plating solution.

FIG. 5 is a schematic bottom view of a holder cover according to the embodiment.

FIG. 6 is a schematic bottom view of a turbulence generating member according to the embodiment.

FIG. 7 is a schematic cross-sectional view illustrating a flow state of the plating solution in a periphery of the turbulence generating member according to the embodiment.

FIG. 8(A) is a schematic bottom view of the holder cover according to Modification 1 of the embodiment. FIG. 8(B) is a schematic bottom view of the holder cover according to Modification 2 of the embodiment.

FIG. 9(A) is a schematic cross-sectional view of the turbulence generating member according to Modification 3 of the embodiment. FIG. 9(B) is a schematic cross-sectional view of the turbulence generating member according to Modification 4 of the embodiment.

FIG. 10(A) is a schematic cross-sectional view of the turbulence generating member according to Modification 5 of the embodiment. FIG. 10(B) is a schematic cross-sectional view of the turbulence generating member according to Modification 6 of the embodiment.

FIG. 11(A) is a schematic cross-sectional view of the turbulence generating member according to Modification 7 of the embodiment. FIG. 11(B) is a schematic cross-sectional view of the turbulence generating member according to Modification 8 of the embodiment.

FIG. 1 is a schematic cross-sectional view of the turbulence generating member according to Modification 9 of the embodiment.

DESCRIPTION OF EMBODIMENTS

The following describes embodiments of the present invention with reference to the drawings. In the following respective embodiments and modifications of the embodiments, an identical reference numeral is attached to an identical or corresponding constitution and a description will be appropriately omitted in some cases. Furthermore, the drawings are schematically illustrated for ease of understanding features of mailers, and a dimensional proportion of each component is not always identical to that of an actual component. For some drawings, X-Y-Z orthogonal coordinates are illustrated for reference purposes. Of the X-Y-Z orthogonal coordinates, the Z direction corresponds to the upper side, and the —Z direction corresponds to the lower side (the direction where gravity acts).

FIG. 1 is a perspective view illustrating the overall configuration of a plating apparatus 1000 of this embodiment. FIG. 2 is a plan view illustrating the overall configuration of the plating apparatus 1000 of this embodiment. As illustrated in FIGS. 1 and 2 , the plating apparatus 1000 includes load ports 100, a transfer robot 110, aligners 120, pre-wet modules 200, pre-soak modules 300, plating modules 400, cleaning modules 500, spin rinse dryers 600, a transfer device 700, and a control module 800.

The load port 100 is a module for loading a substrate housed in a cassette, such as a FOUP, (not illustrated) to the plating apparatus 1000 and unloading the substrate from the plating apparatus 1000 to the cassette. While the four load ports 100 are arranged in the horizontal direction in this embodiment, the number of load ports 100 and arrangement of the load ports 100 are arbitrary. The transfer robot 110 is a robot for transferring the substrate that is configured to grip or release the substrate between the load port 100, the aligner 120, and the transfer device 700. The transfer robot 110 and the transfer device 700 can perform delivery and receipt of the substrate via a temporary placement table (not illustrated) to grip or release the substrate between the transfer robot 110 and the transfer device 700.

The aligner 120 is a module for adjusting a position of an orientation flat, a notch, and the like of the substrate in a predetermined direction. While the two aligners 120 are disposed to be arranged in the horizontal direction in this embodiment, the number of aligners 120 and arrangement of the aligners 120 are arbitrary. The pre-wet module 200 wets a surface to be plated of the substrate before a plating process with a process liquid, such as pure water or deaerated water, to replace air inside a pattern formed on the surface of the substrate with the process liquid. The pre-wet module 200 is configured to perform a pre-wet process to facilitate supplying the plating solution to the inside of the pattern by replacing the process liquid inside the pattern with a plating solution during plating. While the two pre-wet modules 200 are disposed to be arranged in the vertical direction in this embodiment, the number of pre-wet modules 200 and arrangement of the pre-wet modules 200 are arbitrary.

For example, the pre-soak module 300 is configured to remove an oxidized film having a large electrical resistance present on a surface of a seed layer formed on the surface to be plated of the substrate before the plating process by etching with a process liquid, such as sulfuric acid and hydrochloric acid, and perform a pre-soak process that cleans or activates a surface of a plating base layer. While the two pre-soak modules 300 are disposed to be arranged in the vertical direction in this embodiment, the number of pre-soak modules 300 and arrangement of the pre-soak modules 300 are arbitrary. The plating module 400 performs the plating process on the substrate. There are two sets of the 12 plating modules 400 arranged by three in the vertical direction and by four in the horizontal direction, and the total 24 plating modules 400 are disposed in this embodiment, but the number of plating modules 400 and arrangement of the plating modules 400 are arbitrary.

The cleaning module 500 is configured to perform a cleaning process on the substrate to remove the plating solution or the like left on the substrate after the plating process. While the two cleaning modules 500 are disposed to be arranged in the vertical direction in this embodiment, the number of cleaning modules 500 and arrangement of the cleaning modules 500 are arbitrary. The spin rinse dryer 600 is a module for rotating the substrate after the cleaning process at high speed and drying the substrate. While the two spin rinse dryers 600 are disposed to be arranged in the vertical direction in this embodiment, the number of spin rinse dryers 600 and arrangement of the spin rinse dryers 600 are arbitrary. The transfer device 700 is a device for transferring the substrate between the plurality of modules inside the plating apparatus 1000. The control module 800 is configured to control the plurality of modules in the plating apparatus 1000 and can be configured of for example, a general computer including input/output interfaces with an operator or a dedicated computer.

An example of a sequence of the plating processes by the plating apparatus 1000 will be described. First, the substrate housed in the cassette is loaded on the load port 100. Subsequently, the transfer robot 110 grips the substrate from the cassette at the load port 100 and transfers the substrate to the aligners 120. The aligner 120 adjusts the position of the orientation flat, the notch, or the like of the substrate in the predetermined direction. The transfer robot 110 grips or releases the substrate whose direction is adjusted with the aligners 120 to the transfer device 700.

The transfer device 700 transfers the substrate received from the transfer robot 110 to the pre-wet module 200. The pre-wet module 200 performs the pre-wet process on the substrate. The transfer device 700 transfers the substrate on which the pre-wet process has been performed to the pre-soak module 300. The pre-soak module 300 performs the pre-soak process on the substrate. The transfer device 700 transfers the substrate on which the pre-soak process has been performed to the plating module 400. The plating module 400 performs the plating process on the substrate.

The transfer device 700 transfers the substrate on which the plating process has been performed to the cleaning module 500. The cleaning module 500 performs the cleaning process on the substrate. The transfer device 700 transfers the substrate on which the cleaning process has been performed to the spin rinse dryer 600. The spin rinse dryer 600 performs the drying process on the substrate. The transfer device 700 grips or releases the substrate on which the drying process has been performed to the transfer robot 110. The transfer robot 110 transfers the substrate received from the transfer device 700 to the cassette at the load port 100. Finally, the cassette housing the substrate is unloaded from the load port 100.

The configuration of the plating apparatus 1000 described in FIG. 1 and FIG. 2 is merely an example, and the configuration of the plating apparatus 1000 is not limited to the configuration of FIG. 1 and FIG. 2 .

Subsequently, the plating module 400 will be described. Since a plurality of the plating modules 400 included in the plating apparatus 1000 according to this embodiment have similar configurations, only one plating module 400 will be described.

FIG. 3 is a schematic diagram for describing a configuration of the plating module 400 of the plating apparatus 1000 according to this embodiment. The plating apparatus 1000 according to this embodiment is a cup type plating apparatus. The plating module 400 of the plating apparatus 1000 according to this embodiment mainly includes a plating tank 10, an overflow tank 20, a substrate holder 30, a rotation mechanism 40, an elevating mechanism 45, a holder cover 50, and a turbulence generating member 60. In FIG. 3 , the cross-sectional surfaces of the plating tank 10, the overflow tank 20, and the substrate holder 30 are schematically illustrated.

The plating tank 10 according to this embodiment is configured by a container having an opening in its upper side and a bottom. Specifically, the plating tank 10 has a bottom wall portion 10 a, and an outer peripheral wall portion 10 b that extends upward from the outer periphery edge of this bottom wall portion 10 a, and an upper portion of this outer peripheral wall portion 10 b is opened. Although the shape of the outer peripheral wall portion 10 b of the plating tank 10 is not specifically limited, the outer peripheral wall portion 10 b according to this embodiment has a cylindrical shape as an example.

The plating tank 10 internally stores a plating solution Ps. It is only necessary that the plating solution Ps is a solution that contains metallic element ions for constituting the plating Film, and the specific examples are not particularly limited. In this embodiment, a copper plating process is used as an example of the plating process, and a copper sulfate solution is used as an example of the plating solution Ps. Furthermore, in this embodiment, the plating solution Ps contains a predetermined additive. However, it is not limited to this configuration, and the plating solution Ps may have a configuration that does not contain the additive.

The plating tank 10 internally includes an anode 11. A specific type of the anode 11 is not particularly limited, and a soluble anode and/or an insoluble anode may be used. In this embodiment, an insoluble anode is used as the anode 11. A specific type of this insoluble anode is not particularly limited, and platinum, iridium oxide, and the like may be used.

Inside the plating tank 10, a membrane 12 is disposed above the anode 11. Specifically, the membrane 12 is disposed in a position between the anode 11 and a substrate Wf (cathode). The membrane 12 according to this embodiment is, for example, connected to the outer peripheral wall portion 10 b of the plating tank 10 via a holding member 10 d, Furthermore, the membrane 12 according to this embodiment is arranged such that the membrane 12 has a surface direction in the horizontal direction.

The plating tank 10 is internally split into two parts in the vertical direction by the membrane 12. A region partitioned as a side below the membrane 12 is referred to as an anode chamber 13. A region in a side above the membrane 12 is referred to as a cathode chamber 14. The above-described anode 11 is disposed in the anode chamber 13.

The membrane 12 is configured by a membrane that allows metal ions to pass while suppressing the additive contained in the plating solution Ps to pass. That is, in this embodiment, the plating solution Ps in the cathode chamber 14 contains the additive, but the plating solution Ps in the anode chamber 13 does not contain the additive. However, it is not limited to this configuration, and, for example, the plating solution Ps in the anode chamber 13 may also contain the additive. However, even in this case, a concentration of the additive in the anode chamber 13 is lower than a concentration of the additive in the cathode chamber 14. A specific type of the membrane 12 is not particularly limited and a known membrane may be used. Specific examples of this membrane 12 may include, for example, an electrolysis membrane, and as a specific example of this electrolysis membrane, an electrolysis membrane for plating manufactured by Yuasa Membrane Co., Ltd., an ion exchange membrane, and the like may be used.

As in this embodiment, since the plating apparatus 1000 includes the membrane 12, it is possible to suppress a reaction on the anode side causing a component of the additive contained in the plating solution Ps to decompose or react. Accordingly, it is possible to suppress the decomposition or the reaction of the component of this additive generating a component that adversely affects the plating.

The plating tank 10 is provided with an anode supply port 15 for supplying the plating solution Ps to the anode chamber 13. Furthermore, the plating tank 10 is provided with an anode discharge port 16 for discharging the plating solution Ps in the anode chamber 13 from the anode chamber 13. The plating solution Ps discharged from the anode discharge port 16 is then temporarily stored in an anode reservoir tank (not illustrated) and later supplied again from the anode supply port 15 to the anode chamber 13.

The plating tank 10 is provided with a cathode supply port 17 for supplying the plating solution Ps to the cathode chamber 14. Specifically, a part of a portion corresponding to the cathode chamber 14 in the outer peripheral wall portion 10 b of the plating tank 10 according to this embodiment is provided with a protrusion portion 10 c that protrudes into a center side of the plating tank 10, and this protrusion portion 10 c is provided with the cathode supply port 17.

The overflow tank 20 is disposed outside the plating tank 10 and configured by a container with a bottom. The overflow tank 20 is a tank disposed for temporarily storing the plating solution Ps that flows over an upper end of the outer peripheral wall portion 10 b of the plating tank 10 (that is, the plating solution Ps that has overflowed from the plating tank 10). The plating solution Ps supplied from the cathode supply port 17 to the cathode chamber 14 flows into the overflow tank 20, and is then discharged from a discharge port (not illustrated) of the overflow tank. 20, and is temporarily stored in a cathode reservoir tank (not illustrated). Then, the plating solution Ps is supplied again from the cathode supply port 17 to the cathode chamber 14.

In this embodiment, a porous ionically resistive element 18 is disposed above the anode 11 inside the plating tank 10. Specifically, the ionically resistive element 18 is disposed in the cathode chamber 14. Furthermore, the ionically resistive element 18 according to this embodiment is disposed in a position in a vicinity of an upper end of the protrusion portion 10 c. The ionically resistive element 18 is configured by a porous plate member with a plurality of holes (pores). The plating solution Ps below the ionically resistive element 18 is configured to pass through the ionically resistive element 18 upward and then flow above the ionically resistive element 18. This ionically resistive element 18 is a member disposed for achieving the uniformity of the electric field formed between the anode 11 and the substrate Wf. Thus, since the plating apparatus 1000 includes the ionically resistive element 18, the film thickness of the plating film (plated layer) formed on a surface to be plated Wfa of the substrate Wf can effectively achieve uniformity (that is, the uniformity of the plating film).

However, the above-described ionically resistive element 18 is not an essential configuration in this embodiment, and the plating apparatus 1000 may have a configuration without the ionically resistive element 18.

Furthermore, in this embodiment, the anode chamber 13 is provided with an anode mask 19. The anode mask 19 according to this embodiment is arranged such that an upper surface of the anode mask 19 is in contact with a lower surface of the membrane 12. However, it is only necessary that the arranged area of the anode mask 19 is in the anode chamber 13, and it is not limited to the area illustrated in FIG. 3 . In another example, the anode mask 19 may be arranged in a position below the membrane 12 to make a space with the membrane 12. The anode mask 19 has an opening portion 19 a through which electricity that flows between the anode 11 and the substrate Wf passes. Thus, the plating apparatus 1000 provided with the anode mask 19 ensures an improved in-plane uniformity of the plating film of the substrate Wf.

The substrate holder 30 is a member for holding the substrate Wf as the cathode. The substrate Wf is disposed above the anode 11. The substrate holder 30 holds the substrate Wf such that the surface to be plated Wfa of the substrate Wf faces downward. Specifically, the substrate holder 30 according to this embodiment has a first holding member 31 and a second holding member 32. The first holding member 31 holds an upper surface of the substrate Wf. The second holding member 32 holds the outer periphery edge portion of the surface to be plated Wfa of the substrate Wf. The substrate holder 30 holds the substrate Wf such that the first holding member 31 and the second holding member 32 sandwiches the substrate Wf.

The rotation mechanism 40 is a mechanism for rotating the substrate holder 30. Specifically, the rotation mechanism 40 is connected to the substrate holder 30, receives a command from the control module 800, and rotates the substrate holder 30 at least when the plating process is performed on the substrate Wf. As the rotation mechanism 40, a known mechanism can be used, such as a rotation motor. Letter “R” illustrated FIG. 3 is an example of a rotation direction of the substrate holder 30 by the rotation mechanism 40. The rotation mechanism 40 is connected to the elevating mechanism 45. The elevating mechanism 45 is supported by a spindle 46 that extends in the vertical direction. The elevating mechanism 45 is a mechanism for elevating the substrate holder 30 and the rotation mechanism 40 in the vertical direction. As the elevating mechanism 45, the known elevating mechanism can be used, such as a linear motion type actuator.

In the plating process, the rotation mechanism 40 rotates the substrate holder 30 while the elevating mechanism 45 moves the substrate holder 30 downward and immerses the substrate Wf in the plating solution Ps in the plating tank 10. At this moment, a lower surface 50 a of the holder cover 50 described later is also immersed in the plating solution Ps. Subsequently, an energization device causes electricity to flow between the anode 11 and the substrate Wf. Accordingly, the plating film is formed on the surface to be plated Wfa of the substrate Wf.

An operation of the plating module 400 is controlled by the control module 800. The control module 800 includes a microcomputer, and this microcomputer includes a CPU (Central Processing Unit) 801 as a processor, a storage unit 802 as a non-transitory storage medium, and the like. In the control module 800, the CPU 801 controls the operation of the plating module 400 based on commands of a program stored in the storage unit 802.

In this embodiment, one control module 800 functions as a control device that integrally controls controlled units of the plating modules 400, but it is not limited to this configuration. For example, the control module 800 may include a plurality of the control devices, and these plurality of control devices may individually control the respective controlled units of the plating modules 400.

Subsequently, the holder cover 50 will be described. FIG. 4 is a schematic diagram of a peripheral configuration of the substrate Wf in a state where the substrate Wf is immersed in the plating solution Ps. In FIG. 4 , an illustration of the overflow tank 20 is omitted. FIG. 5 is a schematic bottom view of the holder cover 50. In FIG. 5 , a schematic perspective view of a part (A2 portion) of the holder cover 50 is also illustrated, With reference to FIG. 4 and FIG. 5 , the holder cover 50 is disposed to the substrate holder 30. The holder cover 50 is configured to rotate with the substrate holder 30 when the substrate holder 30 rotates.

Specifically, as illustrated in FIG. 4 , the holder cover 50 according to this embodiment is connected to at least a lower surface 32 a of the second holding member 32. More specifically, the holder cover 50 is connected to the lower surface 32 a and an outer peripheral surface 32 b of the second holding member 32. In the plating process, at least the lower surface 50 a of the holder cover 50 is immersed in the plating solution Ps. Furthermore, the lower surface 50 a of the holder cover 50 is positioned below the surface to be plated Wfa of the substrate Wf.

With reference to FIG. 4 and FIG. 5 , the holder cover 50 according to this embodiment is disposed to the second holding member 32 of the substrate holder 30 such that, in the bottom view, the lower surface 50 a of the holder cover 50 surrounds a peripheral area of the surface to be plated Wfa of the substrate Wf Specifically, the lower surface 50 a of the holder cover 50 according to this embodiment has a ring shape with an opening portion 53 in the center portion.

As illustrated in FIG. 5 , the lower surface 50 a of the holder cover 50 is provided with at least one cover groove 51. Specifically, as an example, a plurality of the cover grooves 51 according to this embodiment are disposed. The cover groove 51 extends in a direction intersecting with a rotation direction (or a circumferential direction) of the holder cover 50. Specifically, the cover groove 51 according to this embodiment extends toward a radial direction of the holder cover 50.

In this embodiment, the plurality of the cover grooves 51 each have a constant interval with an adjacent cover groove 51, and are entirely arranged in a circumferential direction around the lower surface 50 a of the holder cover 50. Furthermore, a groove wall portion 52 of the cover groove 51 according to this embodiment is configured by a straight plane.

This cover groove 51 is disposed for, when the holder cover 50 rotates, giving a centrifugal force to the plating solution Ps and giving a flow from an inside (a center side) toward an outside (an outer peripheral side) of the plating tank 10 (this flow state of the plating solution Ps is exemplified in FIG. 7 described below). That is, when the holder cover 50 rotates, the plating solution Ps that exists in the cover groove 51 of the holder cover 50 is given the centrifugal force and thus passes through the cover grooves 51 and flows toward the outside. Accordingly, the flow of the plating solution Ps from the inside toward the outside in the radial direction of the plating tank 10 is accelerated. As a result, the plating solution Ps that exists between the substrate Wf and the ionically resistive element 18 is agitated.

As described above, according to this embodiment, when the holder cover 50 rotates with the rotation of the substrate holder 30, the lower surface 50 a of the holder cover provided with the cover grooves 51 can cause the plating solution Ps to be agitated. Accordingly, the plating solution Ps can be agitated without using the paddle. As a result, the use of the paddle causing the uniformity of the plating film to decrease or the plating apparatus 1000 to increase in size can be suppressed.

According to this embodiment, compared with a case where the paddle is disposed between the ionically resistive element 18 and the substrate Wf, the distance between the ionically resistive element 18 and the substrate Wf can be decreased. Accordingly, the uniformity of the plating film can be effectively achieved. Furthermore, the increase in size of the plating apparatus 1000 can be effectively suppressed.

Subsequently, the turbulence generating member 60 will be described. With reference to FIG. 3 and FIG. 4 , the turbulence generating member 60 is disposed in a position below the substrate Wf and above the anode 11 inside the plating solution Ps of the plating tank 10, Specifically, the turbulence generating member 60 according to this embodiment is disposed in the cathode chamber 14 while being connected to an upper surface of the ionically resistive element 18 via a connecting member 70. However, a connecting method for the turbulence generating member 60 by the connecting member 70 is not limited to the method illustrated in FIG. 4 . In another example, the connecting member 70 may be configured to connect an inner peripheral surface of the outer peripheral wall portion 10 b of the plating tank 10 in the cathode chamber 14 to the outer peripheral surface of the turbulence generating member 60.

The turbulence generating member 60 is a member configured to generate the turbulence in the plating solution Ps that flows from below the substrate Wf toward the substrate Wf (specifically, in this embodiment, the plating solution Ps that flows from below the ionically resistive element 18, passes through the ionically resistive element 18, and then heads toward the substrate Wf). Specifically, the turbulence generating member 60 according to this embodiment has the following configuration.

FIG. 6 is a schematic bottom view of the turbulence generating member 60. FIG. 7 is a schematic cross-sectional view illustrating a flow state of the plating solution Ps in a periphery of the turbulence generating member 60. In FIG. 7 , an illustration of the overflow tank 20 is omitted. With reference to FIG. 4 , FIG. 6 , and FIG. 7 , the turbulence generating member 60 according to this embodiment has an internal flow passage 61. The plating solution Ps that passes through the ionically resistive element 18 and heads toward the substrate Wf flows through the internal flow passage 61.

The internal flow passage 61 according to this embodiment is configured, as illustrated in FIG. 4 , to communicate a lower end 60 a (that is, a portion facing the anode H and the ionically resistive element 18) of the turbulence generating member 60 and an upper end 60 b (that is, a portion facing the substrate WI) of the turbulence generating member 60. Furthermore, as illustrated in FIG. 6 , the internal flow passage 61 according to this embodiment in a bottom view of the turbulence generating member 60 has an Archimedean spiral shape. The internal flow passage 61 with such Archimedean spiral shape is configured such that adjacent internal flow passages 61 are arranged at equal intervals,

FIG. 6 illustrates a projected point P1 where an arbitrary single point on the surface to be plated Wfa of the substrate Wf is projected on the turbulence generating member 60. When the substrate Wf rotates, this projected point P1 draws a circular trajectory C1. In a case where the internal flow passage 61 has an Archimedean spiral shape like in this embodiment, when the substrate Wf makes one rotation, the projected point P1 overlaps with an area of the turbulence generating member 60 other than the internal flow passage 61, only in the portion between a projected point P2 and a projected point P3. Accordingly, when the substrate holder 30 rotates, this embodiment ensures suppressing the hindrance to the electric field between the anode 11 and the substrate Wf by the holder cover 50 as much as possible while agitating the plating solution Ps.

Furthermore, as illustrated in FIG. 4 , the turbulence generating member 60 according to the embodiment is configured such that, when the plating process is performed on the substrate Wf, the upper end 60 b of the turbulence generating member 60 has a clearance 80 with the surface to be plated Wfa of the substrate Wf while being positioned above the lower surface 50 a of the holder cover 50.

As illustrated in FIG. 7 , the plating solution Ps that has passed through the ionically resistive element 18 flows through the internal flow passage 61 of the turbulence generating member 60 and subsequently flows toward the substrate Wf. As described above, according to this embodiment, rotation of the holder cover 50 accelerates a flow from the inside (the center side) toward the outside (the outer peripheral side) of the plating tank 10. Therefore, the plating solution Ps after having flowed through the internal flow passage 61 of the turbulence generating member 60 flows through the clearance 80 between the upper end 60 b of the turbulence generating member 60 and the surface to be plated Wfa of the substrate Wf, thus flowing swiftly from the inside toward the outside in a radial direction of the plating tank 10 along the surface to be plated Wfa of the substrate Wf. Then, the plating solution Ps flows through a portion between the substrate holder 30 and the outer peripheral wall portion 10 b of the plating tank 10, flows over the upper end of the outer peripheral wall portion 10 b of the plating tank 10, and flows into the overflow tank 20.

As illustrated in FIG. 7 , the turbulence generating member 60 according to this embodiment generates the turbulence in the plating solution Ps in the upper end 60 b of the turbulence generating member 60. Specifically, the plating solution Ps that flows between the turbulence generating member 60 and the substrate Wf collides with the upper end 60 b of the turbulence generating member 60, thus causing the turbulence to occur in the plating solution Ps in this upper end 60 b.

Furthermore, the internal flow passage 61 according to this embodiment is provided with a protrusion 62 configured to generate the turbulence in the plating solution Ps that flows through the internal flow passage 61. Specifically, the protrusion 62 according to this embodiment is disposed in the lower end of a flow passage wall portion 60 c (a flow passage wall portion facing outward in a radial direction) of the internal flow passage 61. The cross-sectional shape of this protrusion 62 is not particularly limited, but in this embodiment, as an example, it is a rectangular shape. The plating solution Ps that flows through the internal flow passage 61 partially collides with the protrusion 62, thus causing turbulence to occur in this plating solution Ps.

Thus, according to this embodiment, the turbulence generating member 60 can generate the turbulence in the plating solution Ps that flows toward the substrate WI Accordingly, the plating solution Ps can be effectively agitated.

Furthermore, according to this embodiment, since the internal flow passage 61 is provided with the protrusion 62, compared with a case where the internal flow passage 61 is not provided with the protrusion 62, the turbulence can be effectively generated in the plating solution Ps that flows through the internal flow passage 61. Accordingly, the plating solution Ps can be agitated more effectively.

The protrusion 62 may be disposed not only in the flow passage wall portion 60 c but also in a flow passage wall portion 60 d (a flow passage wall portion facing inward in a radial direction) on the opposite side of the flow passage wall portion 60 c. Alternatively, the protrusion 62 does not have to be disposed in the flow passage wall portion 60 c and may be disposed only in the flow passage wall portion 60 d.

Furthermore, according to this embodiment, since the upper end 60 b of the turbulence generating member 60 has the clearance 80 with the surface to be plated Wfa while being positioned above the lower surface 50 a of the holder cover 50, for example, compared with a case where the upper end 60 b of the turbulence generating member 60 is positioned below the lower surface 50 a of the holder cover 50, the clearance 80 (distance in the vertical direction) can be reduced. Accordingly, the flow rate of the plating solution Ps that flows through this clearance 80 can be effectively increased, and thus the plating solution Ps can be effectively agitated.

Although the specific numerical value of the clearance 80 is not particularly limited, an example of a preferred numerical value in terms of agitating the plating solution Ps of 15 mm or below is preferred, 10 mm or below is more preferred, and 5 mm or below is yet more preferred.

The plating solution agitating method according to this embodiment is achieved by the above-described plating apparatus 1000. That is, the plating solution agitating method according to this embodiment includes rotating the substrate holder 30 by the rotation mechanism 40 with the lower surface 50 a of the holder cover 50 immersed in the plating solution Ps when the plating process is performed on the substrate Wf immersed in the plating solution Ps. The details of this plating solution agitating method are omitted due to the duplication with the above-described description of the plating apparatus 1000. The plating solution agitating method according to this embodiment can exert an operational effect similar to that of the above-described plating apparatus 1000.

[Modification 1] The configuration of the holder cover 50 is not limited to the configuration described in the above-described FIG. 5 and the like. The following describes a modification of the holder cover 50, FIG. 8(A) is a schematic bottom view of a holder cover 50A according to Modification 1 of the embodiment. The holder cover 50A according to this modification is different from the holder cover 50 illustrated in FIG. 5 in that a groove wall portion 52A of a cover groove 51A is arc-shaped in a bottom view. This modification can exert an operational advantage similar to the holder cover 50 according to the above-described embodiment.

[Modification 2] FIG. 8(B) is a schematic bottom view of a holder cover 50B according to Modification 2 of the embodiment. The holder cover 50B according to this modification is different from the holder cover 50A illustrated in FIG. 8(A) in that the cover groove 51A is only partially disposed to the lower surface 50 a of the holder cover 50B. Specifically, the cover grooves 51A according to this modification are, as an example, disposed only on one side with respect to the center line L1 of the holder cover 50B in the bottom view of the holder cover 50B. This modification can exert an operational advantage similar to the holder cover 50A according to the above-described Modification 1.

The holder cover 50B according to this modification may replace the cover groove 51A with the above-described cover groove 51. The holder covers according to the above-described Modification 1 and Modification 2 are examples of the modification of the holder cover 50, and the modification of the holder cover 50 is not limited to the above-described configurations.

[Modification 3] In the above-described embodiment, the cross-sectional shape of the turbulence generating member 60 is not limited to the configuration exemplified in FIG. 4 and the like. The following describes a modification of the turbulence generating member 60.

FIG. 9(A) is a schematic cross-sectional view of a turbulence generating member 60A according to Modification 3 of the embodiment. This FIG. 9(A) schematically illustrates, regarding the turbulence generating member 60A according to this modification, an enlarged cross-sectional surface of an area corresponding to a part A1 of FIG. 4 (FIG. 9(B) to FIG. 12 described below are also similar to this).

The turbulence generating member 60A according to this modification is different from the turbulence generating member 60 according to the embodiment illustrated in FIG. 4 in that the protrusions 62 are disposed not only in the flow passage wall portion 60 c (a flow passage wall portion facing outward in a radial direction) but also in the flow passage wall portion 60 d (a flow passage wall portion facing inward in a radial direction), and in that these protrusions 62 are disposed in a center portion in the vertical direction of the turbulence generating member 60.

Furthermore, the turbulence generating member 60A is different from the turbulence generating member 60 illustrated in FIG. 4 also in that a portion between the protrusion 62 and the upper end 60 b of the flow passage wall portion 60 c and a portion between the protrusion 62 and the lower end 60 a have curved surfaces, in that a portion between the protrusion 62 and the upper end 60 b of the flow passage wall portion 60 d and a portion between the protrusion 62 and the lower end 60 a are inclined surfaces with respect to the horizontal direction, and in that a distal end of the protrusion 62 has a pointed shape.

With this modification, the protrusion 62 of the flow passage wall portion 60 c and the protrusion 62 of the flow passage wall portion 60 d can effectively generate the turbulence.

[Modification 4] FIG. 9(B) is a schematic cross-sectional view of a turbulence generating member 60B according to Modification 4 of the embodiment. The turbulence generating member 60B according to this modification is mainly different from the turbulence generating member 60A illustrated in FIG. 9(A) in that a portion between the protrusion 62 and the upper end 60 b of the flow passage wall portion 60 d and a portion between the protrusion 62 and the lower end 60 a have curved surfaces. Furthermore, the turbulence generating member 60B is different from the turbulence generating member 60A illustrated in FIG. 9(A) also in that the upper end 60 h and the lower end 60 a have pointed shapes.

This modification can exert an operational advantage similar to the turbulence generating member 60A according to Modification 3.

[Modification 5] FIG. 10(A) is a schematic cross-sectional view of a turbulence generating member 60C according to Modification 5 of the embodiment. The turbulence generating member 60C according to this modification is mainly different from the turbulence generating member 60B illustrated in FIG. 9(B) in that the flow passage wall portion 60 d is not provided with the protrusion 62 while the flow passage wall portion 60 d is a plane surface that extends in the vertical direction, and in that a portion between the protrusion 62 and the upper end 60 b of the flow passage wall portion 60 c and a portion between the protrusion 62 and the lower end 60 a are inclined surfaces.

With this modification, the protrusion 62 of the flow passage wall portion 60 c can effectively generate the turbulence.

[Modification 6] FIG. 10(B) is a schematic cross-sectional view of a turbulence generating member 60D according to Modification 6 of the embodiment. The turbulence generating member 601) according to this modification is mainly different from the turbulence generating member 60A illustrated in FIG. 9(A) in that a portion between the protrusion 62 and the upper end 60 b of the flow passage wall portion 60 d and a portion between the protrusion 62 and the lower end 60 a have curved surfaces. This modification can exert an operational advantage similar to the turbulence generating member 60A according to Modification 3.

[Modification 7] FIG. 11(A) is a schematic cross-sectional view of a turbulence generating member 60E according to Modification 7 of the embodiment. The turbulence generating member 60E according to this modification is mainly different from the turbulence generating member 60 illustrated in FIG. 4 in that the protrusion 62 is disposed in a center portion in the vertical direction of the flow passage wall portion 60 c and in that a portion between the protrusion 62 and the upper end 60 b of the flow passage wall portion 60 c and a portion between the protrusion 62 and the lower end 60 a are each provided with a step 63. Even in this modification, the protrusion 62 of the flow passage wall portion 60 c can effectively generate the turbulence.

[Modification 8] FIG. 11(B) is a schematic cross-sectional view of a turbulence generating member 60F according to Modification 8 of the embodiment. The turbulence generating member 60F according to this modification is mainly different from the turbulence generating member 60 illustrated in FIG. 4 in that the protrusion 62 of the flow passage wall portion 60 c is disposed in a center portion in the vertical direction of the flow passage wall portion 60 d and in that a base portion (a boundary of the flow passage wall portion 60 c) of this protrusion 62 is a curved surface 64. This modification can exert an operational advantage similar to the turbulence generating member 60.

[Modification 9] FIG. 12 is a schematic cross-sectional view of a turbulence generating member 60G according to Modification 9 of the embodiment. The turbulence generating member 60G according to this modification is different from the turbulence generating member 60 illustrated in FIG. 4 in that the flow passage wall portion 60 c does not include the protrusion 62, and as a result, the flow passage wall portion 60 c is a plane surface. Even in this modification, as described in FIG. 7 , the upper end 60 b of the turbulence generating member 60G can generate turbulence.

The above-described turbulence generating members according to Modification 3 to Modification 9 are examples of the modification of the turbulence generating member 60 and the modification of the turbulence generating member 60 is not limited to these.

As described above, while the details of the embodiments and modifications of the present invention have been described, the present invention is not limited to the specific embodiments and modifications, and various kinds of modifications and changes can further be made within the spirit of the present invention described in the claims.

REFERENCE SIGNS LIST

-   -   10 . . . plating tank     -   11 . . . anode     -   18 . . . ionically resistive element     -   30 . . . substrate holder     -   40 . . . rotation mechanism     -   50 . . . holder cover     -   50 a . . . lower surface     -   51 . . . cover groove     -   60 . . . turbulence generating member     -   60 a . . . lower end     -   60 b . . . upper end     -   61 . . . internal flow passage     -   60 c, 60 d, . . . flow passage wall portion     -   62 . . . protrusion     -   80 . . . clearance     -   Wf . . . substrate     -   Wfa . . . surface to be plated     -   Ps . . . plating solution 

1. A plating apparatus comprising: a plating tank configured to store a plating solution, an anode being disposed in an inside of the plating tank; a substrate holder disposed above the anode and configured to hold a substrate as a cathode; a rotation mechanism configured to rotate the substrate holder; and a holder cover disposed to the substrate holder and configured to rotate with the substrate holder when the substrate holder rotates, wherein the holder cover is configured to have a lower surface immersed in the plating solution and positioned below a surface to be plated of the substrate, and the lower surface of the holder cover is provided with at least one cover grove extending in a direction intersecting with a rotation direction of the holder cover.
 2. The plating apparatus according to claim 1, wherein the holder cover has a ring shape in a bottom view.
 3. The plating apparatus according to claim 1, further comprising a turbulence generating member disposed in a position below the substrate and above the anode in the inside of the plating tank, the turbulence generating member being configured to generate turbulence in the plating solution flowing from below the substrate toward the substrate.
 4. The plating apparatus according to claim 3, wherein the turbulence generating member has an internal flow passage configured to communicate a lower end of the turbulence generating member with an upper end of the turbulence generating member, and the plating solution heading toward the substrate flows through the internal flow passage, and the internal flow passage in a bottom view of the turbulence generating member has an Archimedean spiral shape.
 5. The plating apparatus according to claim 4, wherein the internal flow passage is provided with a protrusion configured to generate the turbulence in the plating solution flowing through the internal flow passage.
 6. The plating apparatus according to claim 4, wherein the turbulence generating member is configured such that when a plating process is performed on the substrate, the upper end of the turbulence generating member has a clearance with the surface, to be plated of the substrate and is positioned above the lower surface of the holder cover.
 7. An agitating method of the plating solution of the plating apparatus according to claim 1, comprising rotating the substrate holder by the rotation mechanism with the lower surface of the holder cover immersed in the plating solution when the plating process is performed on the substrate. 